Safe Haskell	None

Happstack.Server.Heist

Description

This module provides support for serving compiled Heist templates using Happstack.

The primary function provided by this module is:

heistServe :: (Happstack m) => HeistState m -> m Response

It also provides the initHeistCompiled helper function for creating a HeistState. Though you are free to use other functions from the Heist library instead.

Here is a simple example:

 module Main where

 import Control.Applicative    ((<$>))
 import Control.Monad          (msum)
 import qualified Data.Text    as T
 import Happstack.Server       (dir, nullConf, nullDir, simpleHTTP, seeOther, toResponse)
 import Happstack.Server.Heist (heistServe, initHeistCompiled)
 import Heist                  (getParamNode)
 import Heist.Compiled         (Splice, yieldRuntimeText)
 import qualified Text.XmlHtml as X

 -- | factorial splice
 factSplice :: (Monad m) => Splice m
 factSplice =
     do intStr <- T.unpack . X.nodeText <$> getParamNode
        let res = yieldRuntimeText $
                    do case reads intStr of
                         [(n,[])] ->
                             return (T.pack $ show $ product [1..(n :: Integer)])
                         _ ->
                             return (T.pack $ "Unable to parse " ++ intStr ++ " as an Integer.")
        return $ res

 main :: IO ()
 main =
   do heistState <- do
        r <- initHeistCompiled [(T.pack "fact", factSplice)] [] "."
        case r of
          (Left e) -> error $ unlines e
          (Right heistState) -> return $ heistState
      simpleHTTP nullConf $ msum
        [ dir "heist" $ heistServe heistState
        , nullDir >> seeOther "/heist/factorial" (toResponse "/heist/factorial")
        ]

It uses the following template file (factorial.tpl):

 <html>
   <head>
     <title>Factorial Page</title>
   </head>
   <body>
     <h1>Factorial Page</h1>
     <p>The factorial of 6 is <fact>6</fact></p>
   </body>
 </html>

For more information on using Compiled Heist Templates see:

http://snapframework.com/docs/tutorials/compiled-splices

And also see the Heist Section of the Happstack Crash Course:

http://happstack.com/docs/crashcourse/

Documentation

initHeistCompiled Source

Arguments

:: (MonadIO m, Monad n)
=> [(Text, Splice n)]	compiled splices
-> [(Text, AttrSplice n)]	attribute splices
-> FilePath	path to template directory
-> m (Either [String] (HeistState n))

heistServe :: Happstack m => HeistState m -> m Response Source